Cylinder piston rod units are used for many technical applications and more particularly in the field of motor-vehicles. In this latter field, cylinder piston rod units are e.g. used as gas springs and more particularly as oscillation dampers. Motor-vehicles are used under considerably varying operational temperatures. The operational temperature is not only dependent on the surrounding temperature conditions, but also on the temperature increase which results from operation. So, oscillation dampers of motor-vehicles are frequently subject to a range of operational temperatures which varies between -40.degree. C. and +180.degree. C. It is required that the sealing effect between the piston rod member and the piston rod guiding and sealing unit adjacent one end of a cylinder is maintained within such a wide range of operational temperatures.